In return for allowing the
addition of a third express track, the city required the
demolition of the original brick station houses north of
43rd
Street and
substitution of mezzanine-level facilities. 31st Street is a
representative sample.(Photo by
Charles E. Keevil, from the Walter R. Keevil
Collection)

31st Street was one of the original ten stations of Chicago's
first "L" line, the South Side Rapid Transit. The original station
building was a grade-level structure built in 1892, though it's not
entirely certain what its design looked like. (Most likely, it was a
simple building resembling 39th Street.)

In 1907, as part of an ordinance to allow the South Side Line to
install a third track for express service, all stations north of
43rd Street, including this one, were
required to replace their grade-level facilities with mezzanine-level
stations, clearing the alley way beneath the tracks. Because the
tracks' original elevation was not built with the height clearance of
mezzanine-level stations in mind, the portions of the trestle at
station locations had to be slightly raised, creating roller
coaster-like humps in the structure. The occasional rise and descend
can still be seen in the South Side Green Line's tracks.

In December 1993, while the
CTA was considering various
plans for the Green Line
renovation, one was to close stations at 35th,
Indiana and others, but open a new one at
31st Street. This never came to pass.